We have studied the azimuthal angle distributions of identified charged particles near mid-rapidity region in semi-central Pb+Pb collisions at SPS energies. Our preliminary results show that π
+ ...mesons and protons seem to be emitted in the reaction plane, while out-of-plane for
K
+ mesons. This phenomenon might be explained by the existence of another possible effect such as in-medium potential as well as the collective motion.
The
Δ
++-resonance production in central 158 A GeV
208Pb+
208Pb collisions at the CERN SPS has been studied. The
Δ
++ production was estimated from the invariant mass spectrum of p
π
+-pairs by ...subtracting a mixed event background. The measured
Δ
++ abundance is compared with the results from other experiments at lower energies, and with a model calculation assuming thermal and chemical equilibrium.
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